Showing papers in "Noise & Health in 2008"

Road traffic noise and cardiovascular risk

Abstract: Studies on the association between community noise and cardiovascular risk were subjected to a meta-analysis for deriving a common dose-effect curve. Peer-reviewed articles, objective assessment of exposure and outcome as well as control for confounding and multiple exposure categories were all necessary inclusion criteria. A distinction was made between descriptive (cross-sectional) and analytical (case-control, cohort) studies. Meta-analyses were carried out for two descriptive and five analytical studies for calculating a pooled dose-effect curve for the association between road traffic noise levels and the risk of myocardial infarction. No increase in risk was found below 60 dB(A) for the average A-weighted sound pressure levels during the day. An increase in risk was found with increasing noise levels above 60 dB(A) thus showing a dose-response relationship. A risk curve was estimated for the association using a polynomial fit of the data that can be used for risk assessment and the environmental burden of disease calculations.

Auditory lifestyles and beliefs related to hearing loss among college students in the USA.

Abstract: The purpose of this study was to evaluate the auditory life styles and beliefs of college students with reference to exposure to loud sounds in the context of the health belief model. A survey was administered to 238 (40 men, 198 women) students in the USA. Results suggest that 44% of the students use noisy equipment without ear protection and 29% (69/238) of the students work in noisy environments. Of the 69 who worked in noisy surroundings, only ten reported wearing hearing protection devices although 50 (72.46%) reported tinnitus. The use of hearing protection devices (HPDs) was associated with previous experience with hearing loss and tinnitus. Although 75% of the students were aware that exposure to loud sounds could cause hearing loss, 50% of the students appeared to be exposing themselves to potentially harmful loud music. Furthermore, 46% of the students reported not using HPDs during loud musical activities because they felt that the music was difficult to hear with HPDs. Most students in this study considered hearing loss to be serious but 76% of the students believed that they would not lose their hearing until a greater age. Although 66% of the students had experienced tinnitus, 58% of these students reported not being concerned about it. These results suggest a critical need for promoting healthy hearing behavior among college students. Possible strategies could include improved education, experience with simulated hearing loss for extended periods and availability of cosmetically appealing or invisible HPDs with uniform attenuation across the frequency range.

The relationship between noise frequency components and physical, physiological and psychological effects of industrial workers

Abstract: A corollary to industrialization and urbanization is a significant increase in noise levels. In many industrial settings, the noise levels are such that they are potential health hazards. There are many studies which suggest that prolonged exposures to high noise levels have a negative impact on various aspects of human physiology. However, not much work has been conducted in studying the effects of various noise frequencies in the industrial environment. This paper has made an attempt to identify various noise frequency components to which the workers of six major industries in Mysore (Karnataka State, India) are being exposed, and their effects on the physical, physiological, and psychological systems of the working community with respect to their noisy industrial environment. The study results showed that the sampled industrial workers were repeatedly being exposed to noise of dominant low- and mid-octave band center frequencies. It is found that symptoms such as 'eye ball pressure,' 'awakening from sleep,' 'pains in neck,' 'frequent ear vibration,' 'chronic fatigue,' 'repeated headache,' 'backache,' and 'repeated ear pulsation' are observed to be highly associated with low- and mid-octave band center frequency noise exposure among the sampled workers. Furthermore, among the major psychological symptoms identified to be associated with octave band center frequencies, it is evident that 'irritability' is highly associated with low- and mid-octave band noise frequency characteristics.

Employment and acceptance of hearing protectors in classical symphony and opera orchestras.

Abstract: Objectives: Prior to this study, it was not clear how familiar orchestral musicians were with the various insertable models of hearing protectors The present study focuses on musicians and entertainers and proposes the maintenance of a noise exposure limit through the use of a hearing protector Materials and Methods: This study was conducted by distributing a questionnaire to musicians ( n = 429) in nine orchestras in order to obtain information on the use of hearing protection and the musicians' hearing sensitivity Results: Hearing protectors were found to be seldom used by orchestral musicians During orchestral rehearsals, 80% of the respondents indicated that they knew about them A gap emerged between what seemed most important to musicians in hearing protectors and what was provided by the manufacturers Conclusions: The subject of hearing protection in orchestral musicians should be investigated with a multidimensional approach which considers the following in equal measure: legal regulations, the requirements and limits of the music sector and the individual characteristics of the musicians involved

Hospital contacts for noise-related hearing loss among Danish seafarers and fishermen: a population-based cohort study.

Abstract: Aims: Noise-induced hearing loss (NIHL) is a leading occupational disease and some seafarers and fishermen may be at high risk. We present here standardized hospital contact ratios (SHCRs) for hearing loss among Danish seafarers and fishermen. Materials and Methods: Cohorts of all Danish seafarers registered by the Danish Maritime Authority (DMA) and fishermen retrieved from a 1989-1998 pension registry were linked to the nationwide Occupational Hospitalisation Registry (OHR) with follow-up for NIHL from 1994 to 2003, using rates specific for age and calendar time for the entire Danish workforce as a reference. Results: We found high SHCRs for NIHL: 165 [95% confidence interval (CI) 131-206] among officers, 113 (79-157) for nonofficers and 119 (85-162) for fishermen. The increased SHCR for hearing impairment among seafarers was solely found in engine room personnel (SHCR = 222; 95% CI 178-277). Compared to other seafarers, the engine room personnel had a relative risk ratio of 2.39 (95% CI: 1.74-3.26). Short-term employment is common in many trades. No duration response pattern was observed which may suggest a secondary healthy worker effect. Conclusions: These findings indicate that hearing problems are frequent among men who work in the engine rooms on ships. Long-term cumulative effects of employment were not shown.

Audiological findings in individuals exposed to organic solvents: Case studies

Abstract: Millions of people around the world are exposed to industrial organic solvents such as toluene and xylene in the manufacturing sectors. Solvents are neurotoxic substances that are detrimental to the functioning of the nervous system, including the central auditory nervous system (CANS). This study investigated hearing and auditory processing in seven individuals with a history of exposure to industrial solvents. A battery of audiological tests was administered to all subjects: pure tone, speech, and impedance audiometry, otoacoustic emissions tests, auditory brainstem responses, middle latency responses, as well as the SCAN-A and R-SPIN tests with low predictability sentence lists. All individuals in this study exhibited findings consistent with retrocochlear and/or central abnormality. Two of the seven subjects in this study had normal pure tone thresholds at all frequencies bilaterally, yet showed abnormal retrocochlear/central results on one or more tests. The auditory test battery approach used in this study appears to be valuable in evaluating the pathological conditions of the CANS in solvent-exposed individuals.

Noise levels in a tertiary care hospital.

Abstract: High levels of noise in hospitals may interfere with patient care services, the doctor-patient relationship and medical education activities. The aim of this study was to assess the noise level at different places in a tertiary care hospital and suggest measures to reduce the noise. Sound levels of fourteen places inside the hospital were recorded using a Digital Sound Level Meter . A total of 20 readings were taken at three minute intervals between successive recordings during the morning (9 to 10 a.m.) and evening hours (6 to 7 p.m.) and analyzed using simple descriptive statistics. The mean equivalent sound pressure levels (Leq) during the morning and evening hours were 70.38 and 64.46 dB(A) respectively. During the morning hours, the maximum Leq was observed in the mortuary (76.70 dBA) whereas the minimum Leq was in the intensive care unit (I.C.U) (58.34 dBA). The maximum and minimum Leq during evening hours were recorded at O.G (Obstetrics and Gynecology) ward (71.86 dBA) and mortuary (57.08 dBA) respectively. The morning hours showed higher levels of noise in most of the places probably due to overcrowding and higher vehicular movement. This study highlights the need for noise monitoring and control measures inside hospital areas.

What do we know about hearing protector comfort

Abstract: The purpose of the present article is to review comfort studies on hearing protector devices. Comfort is probably the most important dimension for long-term worker acceptance and effective wear of hearing protectors in noise. A short digression has been made to introduce comfort work from the textile and clothing industries where models of comfort have been attempted and comfort research is much more sophisticated. Finally, presented are some recent efforts by NIOSH to examine issues of hearing protector comfort in greater detail. These efforts include a field study of a semi-custom earplug hearing protector.

Noise levels in Greek hospitals

Abstract: High noise levels have been recognized as a serious problem in hospital environments during both night- and daytime, and have been associated with a negative impact on patients' health status. The aim of this study was to measure and detect differences in noise levels between an ICU and a pulmonary ward in two general hospitals in Greece. Methods: Noise measurements were recorded in one-hour intervals using the Cirrus CR: 245/R2 Environmental Noise Analyzer in a 30-bed pulmonary ward and in a 16-bed general ICU for seven consecutive days. Results: Noise levels detected in the ward were significantly lower than those detected in the ICU (52.6 ± 8.2 dB vs 59 ± 2.2 dB, P < 0.001). Noise levels decreased significantly during the course of the day in the ward, reaching the lowest limits during the night shift. This was not observed in the ICU and this pattern was constant during the periods monitored in both departments. Conclusion: Noise levels measured in the ward and in the ICU were high, significantly exceeding the highest permitted values for hospitals. The latter was more obviously recorded in the ICU.

High sound pressure levels in Bavarian discotheques remain after introduction of voluntary agreements

Abstract: While no legal rules or regulations exist in Germany, voluntary measures were introduced to achieve a reduction of sound pressure levels in discotheques to levels below 100 dB(A). To evaluate the current levels in Bavarian discotheques and to find out whether these voluntary measures ensured compliance with the recommended limits, sound pressure levels were measured in 20 Bavarian discotheques between 11 p.m. and 2 a.m. With respect to the equivalent continuous A-weighted sound pressure level for each 30-minute period (L Aeq,30min ), only 4/20 discotheques remained below the limit of 100 dB(A) in all time periods. Ten discotheques had sound pressure levels below 100 dB(A) for the total measurement period (L Aeq,180min ). None of the evaluated factors (weekday, size, estimated age of attendees, the use of voluntary measures such as participation of disc jockeys in a tutorial, or the availability of a sound level meter for the DJs) was significantly associated with the maximal L Aeq, 30min . Thus, the introduction of voluntary measures was not sufficient to ensure compliance with the recommended limits of sound pressure levels.

Occupational noise in rice mills.

Abstract: Background: A major occupational hazard for the workers in rice mills is the noise during the operation of various machines. A noise survey was conducted in the workrooms of eight renowned rice mills of the north-eastern region of India established during the period between 1980 and 1985. The rice mills were selected on the basis of the outcome of a walk-through noise survey involving several rice mills of the region. A noise survey map of each rice mill was drawn to identify the predominant noise sources and the causes of high noise in the workrooms of the rice mill. The sound-pressure level (SPL) in the workrooms of the rice mill varied from 78 to 92 dBA. The paddy cleaner, rubber roll sheller, compartment separator, rice cleaner, auxiliary sieve shaker and an electric motor without enclosure were found to be the predominant noise sources in the workrooms of the mill. The causes of high noise in the rice mills may be attributed to the use of a long flat belt drive, crank-and-pitman mechanism, absence of an electric motor enclosure, poor machine maintenance and inadequate acoustic design of the workroom of the rice mill. About 26% of the total labourers were found to be exposed to higher levels of noise than 85 dBA. Subjective response indicated that about 26% of the total labourers felt noise interferes in their work and about 49% labourers were of opinion that noise interferes with their conversation. Context: Noise from machines in the rice mills was found to be the major occupational hazard for the rice mill workers. The predominant noise sources need to be identified and the causes of high noise need to be studied to undertake the appropriate measures to reduce the noise level. Aims: To identify the predominant noise sources and their distributions in rice mills, to study the causes of high levels of noise in rice mills and to examine the response of the workers towards noise. Settings and Design: A noise survey was conducted in eight renowned rice mills of the north-eastern region of India. The mills were selected based on a walk-through survey conducted for the identification of rice mills with high noise. A noise survey map of each rice mill was collected by following the guidelines of Canadian Centre for Occupational Health and Safety (CCOHS). The distribution of high noise in rice mills was studied and the causes of high noise were identified. The subjective response to noise in rice mills was assessed by conducting personal interview with all the workers of the rice mills using a structured form. Methods and Material: The guidelines of CCOHS were followed during the noise survey. A sound level meter (SLM; Model-824) was used to record the noise level at each grid point marked at 1 m × 1 m. SPL in weighting scale A and the noise spectrum were recorded at each grid point for 30 s and data were stored in SLM. A noise survey map of equivalent SPL was drawn for each rice mill by drawing contour lines on the sketch of the rice mill between the points of equal SPL. The floor area in the rice mill where SPL exceeded 85 dBA was identified from the noise survey map of each rice mill to determine the causes of high levels of noise. In order to study the variation in SPL in the workroom of the rice mill throughout the shift, equivalent SPL was measured at six locations in each rice mill. The subjective response to noise in rice mills was assessed by conducting personal interview with all the workers of the rice mills using a structured form. Demographic information, nature of work, working hours, rest period, experience of working in mill, degree of noise annoyance, activity interference, and psychological and physiological effects of machine noise on the worker were asked during the interview. Statistical Analysis Used: Nil. Results: The noise survey in eight select rice mills of the major paddy-growing regions of India revealed that the workrooms of five rice mills had SPL more than 85 dBA in the locations where workers were engaged for most of the time. The predominant noise sources in the rice mills were paddy cleaner, rubber roll sheller, compartment separator, rice cleaner, sieve shaker and an electric motor without enclosure. The causes of high noise in the rice mills may be due to the use of a long flat belt drive, crank-and-pitman mechanism, absence of an electric motor enclosure, poor machine maintenance and inadequate acoustic design of the workroom in the rice mill. In general, a well-maintained rice mill with each machine being run individually using an electric motor produced less noise than that being run using a single electric motor along with flat belt drives. The normal working period in the rice mill was 48 h/week and it was 56 h/week during the peak season of rice milling. About 26% of the total workers were exposed to noise of more than 85 dBA. Subjective response indicated that about 26% of the total workers felt noise interferes in their work and about 49% workers were of opinion that noise interferes with their conversation. Conclusions: The workers in the rice mills are exposed to high noise, which will have detrimental effect on their health. Apart from undertaking appropriate noise control measures, preventive maintenance of machines needs to be given due importance in all the rice mills.

Fraction of work-related accidents attributable to occupational noise in the city of Botucatu, Sao Paulo, Brazil

Abstract: Background: Noise is the most common agent of occupational exposure. It may induce both auditory and extraauditory dysfunction and increase the risk of work accidents. The purpose of this study was to estimate the fraction of accidents attributable to noise occupational exposure in a mid-size city located in southeastern Brazil. Materials and Methods: In this population case-control study, which included 108 cases and 324 controls, the incidence rate ratio of work accidents controlled for several covariables was obtained by classifying occupational noise exposure into three levels, as well as determining the prevalence in each level. Results: Based on these data, the attributable fraction was estimated as 0.6391 (95% CI = 0.2341-0.3676), i.e., 63% of the work accidents that took place in the study site were statistically associated with occupational noise exposure. Discussion: The causes of this association as well as its implications in the prevention of work accidents are discussed.

Elementary school children's knowledge and intended behavior towards hearing conservation.

Abstract: The purposes of the study were to investigate children's knowledge about hearing conservation, the types of protective behaviors they would adopt towards noise, the agreement between children's knowledge and intended behaviors in hearing protection, and reasons why they would not take any protective action against noise. A questionnaire was administered to 479 4 th and 5 th graders in their school classrooms. Results indicated that children scored low (62.01%) on this hearing conservation questionnaire. They scored the highest in strategies of hearing protection (69.89%), followed by their knowledge in general hearing health (62.56%) and noise hazards (49.65%). Only 55% of the children knew that hearing protective devices could protect them against noise. Approximately 28% of the children did not intend to adopt any protective behavior towards noise and the major reason for this was a lack of knowledge. Children's knowledge and their noise-protective behavior were correlated ( P < 0.05). However, possessing knowledge did not guarantee that children would adopt such behaviors when they were exposed to loud sounds. Hence, it is important to increase children's knowledge about hearing protection and hazardous noise as well as to encourage actual protective actions.

Monetary value of undisturbed sleep.

Abstract: Study Objectives: To design a national antinoise policy, we need to know the monetary value that people attach to the reduction of sleep disturbance due to road traffic noise. Principles: Patients with obstructive sleep apnea syndrome (OSAS) controlled by nasal continuous positive airway pressure (nCPAP) underwent one-to-one structured interviews to determine the monetary value of their resultant undisturbed sleep. This was then converted into a value for sleep undisturbed by noise, using a severity ratio. Setting: Outpatient interviews in 67 OSAS patients (54 males, 28 to 73 years old) managed by the Center for Sleep Medicine, Kantonsspital, St. Gallen, Switzerland. Materials and Methods: The interview questions addressed the outcome and difficulties of nCPAP therapy, the self-rated severity of pretreatment sleep disturbance and self-rated monetary value of sleep improvement. Thirteen OSAS patients who had also experienced noise-related sleep disturbance rated its severity on a visual analogue scale (VAS). Results: The mean monetary value of nCPAP-controlled sleep disturbance was Swiss francs (CHF) 70/night (CHF1 = US$ 0.877, year end 2004; 25 th and 75 th percentiles: CHF 35 and CHF 100). Interviewees maintained this high estimate after learning that the actual treatment costs were only approximately 6 CHF/night. A severity ratio ranging from 2.3:1 to 4.7:1 for sleep disturbance resulting from OSAS or from noise was derived from patients' responses and literature. The value of noise-free sleep was CHF 7.45-23.81 per night. Conclusion: Sleep undisturbed by noise has a remarkably high monetary value for people, which should be considered in political decision-making.